The purpose is to assess the safety profile and performance of a femoral resurfacing implant for localized chondral lesions.

The implant's safety profile will be assessed by incidence of any subject having any of the seven identified implant-related clinical undesirable side effects. This will be analyzed with a one-side exact binomial test on significance level 0.05, at 24 months post-operatively.

Inclusion Criteria:

1. Male or female
2. Age 30 ≤ 65 years
3. Chondral defects of the femoral cartilage ICRS grade 3 (severely abnormal cartilage defects > 50% of the cartilage depth) or grade 4 (severely abnormal, through the cartilage depth) on medial or lateral femoral condyles
4. Cartilage lesion area < 3.2 cm2 (diameter < 2 cm)
5. Failed earlier conservative or surgical interventions such as lavage, abrasions, drilling or microfracture
6. VAS-pain symptom >40 for more than 6 months
7. The arthroscopic finding corresponds to the expected; size of cartilage lesion is correct and no other significant pathology (see CIP, "Intra-operative check-list", Appendix I)
8. Capable of completing self-administered questionnaires
9. Willing to comply with the follow-up requirements of the study
10. Signed informed consent

Exclusion Criteria:

1. BMI ≥ 35 kg/m2 (severe obesity)
2. Instability or deficiency of soft tissues, vascular or muscular insufficiency
3. Metabolic disorders which may impair bone formation
4. Diabetes mellitus
5. Smokers
6. Diagnosis of a concomitant knee injury which the Investigator appreciates may interfere with study participation (i.e. may confound efficacy assessment or healing at the involved knee joint level)
7. Irresolvable joint pain or loss-of-function with an undeterminable cause
8. Diagnosis of a concomitant meniscal injury in involved knee that requires surgical intervention
9. Loss of joint space on standing radiographs (≥ 1 on Ahlbäck-scale (0-5))
10. Avascular necrosis
11. Infections, systemic or local
12. Known metal allergies
13. History of inflammatory arthritis
14. Pregnancy
15. Pacemaker implant
16. History of drug or substance abuse
17. Systemic administration within 30 days prior to the study of any type of corticosteroid, antineoplastics, immune stimulating or immunosuppressive agents
18. Participation in another clinical trial using an investigational new drug or device within 30 days of entrance into this study.
19. Condition that may have an impact on the outcome of the investigation as judged by the Investigator.